Topic: DMD0001

ALDEV - Deviation Alarm

The Deviation Alarm instruction (ALDEV) monitors the Input and sets the selected alarm bit locations if the Input has changed (deviated) from the Set Point by more than the Deviation Limit.

Parameters:

Note: Use the F9 key (Element Browser) or Down-Arrow key (Auto-Complete) at any time to see a complete list of the memory locations that are valid in the current field of the instruction.

Input - designates the location to monitor. This can be any readable numeric location.

Set Point - specifies the value which the deviation is measured from. The Set Point can be any constant value or any readable numeric location.

Deviation Limit - specifies the maximum allowable change of the Input value from the Set Point value. Deviation Limit can be any constant value or any readable numeric location.

Positive Alarm - (if selected) designates a bit location to turn ON if the Input value is greater than the SetPoint by more than the Deviation Limit, otherwise the bit will be turned OFF. This can be any writable bit location.

Negative Alarm - (if selected) designates the bit location to turn ON if the Input value is less than the SetPoint by more than the Deviation Limit, otherwise the bit will be turned OFF. This can be any writable bit location.

See Also:

• ALDEV - Deviation Alarm

• ALHILO - High/Low Alarm

• ALRATE - Rate of Change Alarm
   

• PID - Closed Loop Controller

Related Topics:

• Getting Started with PID Loops

• Using the PID View

• Using the PID Overview

• Using the PID Process Simulator in the Do-more Simulator

Rung Example: